DE2138197A1 - Means for the electrolytic production of shiny tin coatings - Google Patents

Description

Dr. F. Zumsteip © er «. - Dr. L ·. Ashman η Dr. R. Koe-nigsberger - Dlpl.-Phys. R. Hoizbauer - D · ■. F. Zurnsteln Jun.

PATENT LAWYERS

TELEPHONE: COLLECTIVE NO. 225341

TELEGRAM- ZUMPAT

CHECK ACCOUNT: MUNICH 91139

BANK ACCOUNT:
BANK H. HOUSES

0389-71
US 59,749

IMASA, Paris / France

Means for the electrolytic production of shiny pewter =

coatings

The invention relates to means, doh. a bath, a composition for making the bath and a method for its use, for the electrolytic production of shiny tin coatings.

Acid tinning baths for producing shiny tin coatings by electrolytic means are already known. These Baths contain sulfate, sulfonate or pluoborate ions, a reducing agent such as! formalin, a non-ionic surface-active Agent and as a gloss-producing agent (hereinafter referred to as "glossier") either an aldehyde, which is an aromatic one or heterocyclic nucleus and in which the carbonyl radical directly with the aromatic or heterocyclic Core is connected, or a «, ß-olefinically unsaturated Garbo =

Ί -z 13

nyl compound, such as Δ * ~ I) ih.ydro-o ~ tolylaldeh.yd ₉ Δ '-dihydrobenzaldehyde, the aldehyde of cinnamic acid, the aldehyde of a ~ ethylcinnamic acid, 2,4-hexadienal, 3 = ponnyl = 5 » 6-dihydro-2,6-di «methylpyran, benzalacetone, benzalacetophenone, 2-benzalcyclohexa« non, vinylphenylketone, p-chlorobenzalaeetorx, 2-cinnamylthiophene, 2 = (ω ~ acetyl!) - vinylfuran, 2- (w-benzoyl) -vinylfuran, p-Cl-phenyl-

109886/1984

styryl ketone, isobutyl styryl ketone, w-acetyl ethyl cinnamate and
p-tolyl styryl ketone. The addition of acrolein as such to acidic electrolytic tin-plating baths has hitherto not permitted the production of shiny electrolytic tin coatings. In addition, the highly tear-inducing and irritating properties of acrolein, as well as its toxic nature, make the use of this compound difficult.

There are also already known acidic tin-plating baths for the production of shiny tin coatings by electrolytic means, which on the one hand contain sulfate, sulfonate and fluoborate ions, on the other hand
a nonionic surface-active agent, on the other hand also a primary gloss, an olefinically unsaturated organic carbonyl compound from the group of the compounds listed above and on the other hand, finally, as a secondary gloss, a polymerizable organic compound that is able to reduce the overvoltage that causes the release of hydrogen of a tin cathode, which is
this compound to one from the group of acrylic acid,
Methacrylic acid, acrylamide, methacrylamide, glyeyl acrylate, propylene glycol acrylate, dimethylaminoethyimethacrylate, glyoxal,
Glutaric acid dialdehyde, a-hydroxyadiplic acid aldehyde, N-vinylpyrrolidone, p-diethylaminobenzidehyde, !! - vinylcarbazole, 2-vinylpyridine, tetrahydrofuran, vinyl acetate and alkyl glycidyl ether.

Finally, acidic electrolytic tinning baths are used for the production of bright tin coatings on electrolytic surfaces
Known ways that a primary shimmer of the formula X-CH = CH-Y
contain, in which X is the phenyl, furfuryl or pyridyl radical and Y is a hydrogen atom or a formyl, carbonyl, alkyl,
Mean hydroxyalkyl, formylalkyl or acyl radical of a carboxylic acid. Formaldehyde and certain imidazoline derivatives serve as secondary glossers in such baths, especially when used with nonionic wetting agents.

The aim of the invention is especially equipment for manufacturing

109886/1984

of shiny tin coatings by electrolytic means, which correspond better to the various wishes of the practice than those already available.

In order to achieve this, according to the invention, as a shimmer (shimmering Agent) in the baths of the type in question, the tin ions, free acid and a nonionic surfactant Contain agents, a soluble acrolein or methacrolein polymer-isate with an essentially linear molecule and a low molecular weight in the form of a homopolymer or Copolymer used. The homopolymers and copolymers of acrolein or methacrolein used according to the invention have a molecular weight, hereinafter abbreviated to PM, of about 300 to 900. The exact structure of the one in question Polymer is not known. In theory, they contain recurring ones Structural units that contain the aldehyde and correspond to the formula:

H-C = O

in which η is the number of structural units of the type in question in the polymer molecule and R denotes a hydrogen atom or the methyl radical.

The polymers used according to the invention are prepared by polymerizing acrolein or methacrolein monomers (Homopolymers) or of acrolein or methacrolein in conjunction with at least one other reagent or copolymerizable Comonomers (copolymers) at the polymerization temperature and in an aqueous, alkaline, liquid medium,

1.09886 / 1984

preferably in a dilute aqueous solution of a weak one Base, such as an alkali metal carbonate, for example sodium carbonate, Potassium carbonate or potassium bicarbonate. Aqueous solutions of other alkaline substances, for example potassium hydroxide or triethylamine, can also be used.

The polymerization is initiated at ambient temperature and if necessary, the reaction medium during the Polymerization cooled. In this way a soluble, essentially linear polymer with a low molecular weight is obtained (PM), which theoretically has the following formula in the case of acrolein and methacrolein homopolymers:

HIGH ₀ CR-

^ά \
HC = O

R.
CH ₂ -C

H-C = O

CH ₂ CRHC = O

in which η is the number of monomer units and R is a hydrogen atom or the methyl radical. In reality, the number of aldehyde radicals in such a polymer molecule is low and they are believed to be only about $ 15 to $ 20 of the theoretical number amounts to. It is assumed that the low content of aldehyde residues in the polymers is due to the conversion of these residues into ether, Hydroxy or ester chain links and sometimes in aldol is. The polymers used according to the invention, whether they are homopolymers or copolymers, are in the classic organic solvents, for example in alkanols with 1 to 3 carbon atoms, in methyl ethyl ketone, Acetone, and also soluble in dimethylformamide.

The procedure in detail for the preparation of the acrolein homopolymers is followed so that one introduces water into a reactor and

109886 / 198A

add acrolein to the mixture while stirring continuously with a magnetic stirrer to keep the ingredients moving. That Acrolein is slowly added to the water. The alkaline substance, for example the weak base, is then added to the mixture inside the reactor while the mixture is constantly being stirred. such as sodium carbonate or potassium carbonate, added. The mixture is then poured into the reactor while stirring is continued this mixture is preferably a primary amine, for example a primary aromatic amine, such as o-, m- or p ~ toluidine or Aniline added. To remove the exothermic heat of reaction, the reaction mixture inside the reactor with the help of any suitable indirect cooling device, for example by a water jacket, cooled. The reaction mixture is left a sufficient time in the reactor, for example about 2 hours, to allow the polyacrolein to form. The polyaerolein is then separated from the aqueous phase, for example by decanting, and it is then generally with Water washed. The polyaerolein is then generally used dissolved in a water-miscible, liquid, organic solvent, e.g. isopropanol. As a variant, the alkaline Substance, e.g. the weak base, such as sodium carbonate or potassium carbonate, can be added to the aqueous liquid and then the acrolein and primary amine are slowly and separately added to the liquid mixture using a with a Faucet provided! Apart from this point, the procedure used in this variant is the same v / how it is described above. The methacrolein homopolymer. can also be done using the procedure just described produced v / earth.

During the production of the acrolein polymer there should be good ventilation and there should be no sparks and free Flames to be in the vicinity, at least during the initial stage of implementation. Appropriate security conditions are also recommended for the production of the methacrolein polymer. In the case of the single polymer aerol, it is also advantageous to use the

109886/1984

Protect the contents of the reactor by a nitrogen atmosphere and use a closed reaction vessel.

In the production of acrolein copolymers with different mispolymerizable compounds as indicated elsewhere in the description is that used Production method very similar to that described above; the acrolein and at least one other copolymerizable compound can be added to the water together in the form of a previously prepared mixture or separately. In the preparation of the methacrolein copolymers with various misehpolymerizable Compounds also given elsewhere in the description is the manufacturing process very analogous to that described above, methacrolein and at least one other copolymerizable compound be added together in the form of a previously prepared mixture or separately to the water.

Acrolein and methacrolein are represented by the following general formula marked:

RH
II
CH ₂ = CC = O

in which R denotes a hydrogen atom or the methyl radical.

The nonionic surfactant used in the present invention also exerts a luster effect on the electrolytic tin coating from in addition to its effect as a wetting agent, due to which it gives the polymer good wettability. Because of his The nonionic surface-active agent can act as a secondary gloss in the electrolytic tin coating Be viewed within the scope of the invention, while the acrolein or methacrolein polymers are then viewed as the primary shine and must be designated. However, if the surfactant

109886/1984

is not regarded as a secondary shine, the acrolein or methacrolein polymer are as simple shine (shine-making Medium).

Other additives used in the electrolytic tinning according to the invention Polyvinylpyrrolidone, which serves as a molecular complexing agent, and additional isopropanol can be used, for example to facilitate the solubilization of the acrolein or methacrolein polymer. The electrolytic tinning bath I, which contains the homopolymer or copolymer (according to According to a preferred embodiment of the invention described further below, it can be terminated by a Schiff base can) and that also the .nonionic surface-active agent contains, a primary aromatic amine, for example o-, m- or p-toluidine or aniline, can also be added. It was namely, found that the separate addition of such a primary aromatic amine to the electrolytic bath resulted in formation an electrolyte! see tin coating with a noticeable leads to better gloss than it is obtained if only the preferred homopolymer or copolymer, which is by a Schiff base is complete, and the nonionic surfactant Funds used.

The amounts of acrolein or methacrolein polymer and of nonionic polymer added to the electrolytic tinning bath Surfactants are selected so that one shiny electrolytic tin coating, these amounts can vary widely. Satisfactory results will be with a small amount of each of the two compounds, i.e. with about 2 to 30 ml of an acrolein or methacrolein polymer solution, whose concentration of polymer is about 10 wt .- ^, and with about 2 to 30 ml of nonionic surfactant Means received per 1 bath. It is possible to increase these amounts, the upper limit being due to economic considerations and is determined by the solubility of the homo- or mixed polymer in the bath, it is also possible to use somewhat lower

109886/1984

Quantities to use. The same applies to the amounts of nonionic surfactant. The temperature of the electrolytic tinning is during the formation of the coatings is usually about 18 to 30 ⁰ C. .The invention electrolytic tinning provide glatteund shiny tin coatings within a sufficiently large current intensity range which extends from low values to high values.

When carrying out the electrolytic tinning, the object to be tinned is cathodically polarized in the bath and one conducts a direct electrical current from this anode through the bath to the cathode. But you can also use other anodes in the same Attach the bath.

Any suitable nonionic surfactant can be used in the practice of the invention. Examples of such surfactants Means are "Triton IF-101", a polyethylene alcohol of wonylphenol, "Triton X-100", a polyether alcohol of octylphenol, and other alkylaryl polyether alcohols described in the book Rohm and Haas Surfactants, Handbook of Physical Properties "der Pa. Societe Rohm and Haas Co., Independance Mall West, Philadelphia, Pa. 19105 »USA. Other examples of nonionic surfactants that can be used in the present invention are those sold under the trade name "Igepal CO-710", "Igepal CO-730", "Igepal CO-630" and "Igepal -00-430" from the Antara Chemical Company.

The glossing agents according to the invention include a mixture of soluble, essentially linear acrolein or methacrolein polymers with low molecular weight and a diluent or carrier that is miscible therewith. The diluent or carrier consists generally from a water-miscible, liquid, organic solvent, e.g. an alkanol with 1 to 3 carbon atoms, Methyl ethyl ketone, acetone, dimethylformamide, ethylene glycol or glycerol, in which the acrolein or methacrolein polymer

109886/198 4

is solved, the whole being, for example, a solution. As indicated above, the polymer can be a homopolymer or a copolymer.

The amount of acrolein or methaerolein polymers in the inventive Giancer additives used can vary within wide limits. So the acrolein or methacrole.in polymers .. (Homopolymers or copolymers) in an amount of about 5 to about 95% by weight, based on the total additive composition, are present. The nonionic surface-active agent can also be used in the structure of the gloss additive according to the invention occur and in this case it is in an amount between

about 10 and about 50 wt .-? &, based on the total additive composition, before.

According to a variant, the acrolein or methacrolein polymers can as such can be added to the acidic electrolytic tin plating bath, but this solution is not a preferred one Embodiment of the invention.

The acrolein or methacrolein polymer used according to the invention has little or limited solubility in the aqueous electrolytic tinplating baths, but it is sufficiently soluble in these baths to be effective as a shine. Copolymers of acrolein or methacrolein and at least a copolymerizable compound different therefrom, which is used as a brightener in the tin-plating baths according to the invention can be, e.g. Acrolein / Methacrolein ^ mixed poly ^ merizates, copolymers of acrolein or methacrolein and crotonaldehyde, copolymers of acrolein or methacrolein and formaldehyde, copolymers of acrolein or methacrolein and acrylamide, copolymers of acrolein or methacrolein and vinyl acetate and copolymers of acrolein, methacrolein and urea. The copolymers can do the same Polymerization processes are prepared as described above for the preparation of the homopolymers and

109886/1984

that consists in that the comonomers or polymerizable Substances in the environment of a dilute aqueous alkaline solution, e.g. a dilute aqueous solution of potassium carbonate, sodium carbonate or potassium bicarbonate are mixed polymerized. The acrolein / methacrolein copolymers are produced by mixing acrolein and methacrolein with each other in a molar ratio of about 4: 1; the aerolein / crotonaldehyde copolymers are made by adding acrolein and crotonaldehyde in a molar ratio usually between about 1: 1 and 4: 1 mixed polymerized; the acrolein / formaldehyde " Copolymers are produced by adding acrolein and formaldehyde in a molar ratio, usually between about 4: 1 and about 3: 2 mixed polymerized; the acrolein / acrylamide copolymers are prepared by adding acrolein and acrylamide in a molar ratio each usually between about 4 »9: 0.1 and about 4s1 mixed polymerized; the acrolein / vinyl acetate copolymers are made by adding acrolein and vinyl acetate in a molar ratio usually between about 4.9: 0.1 and about 4: 1 mixed polymerized: and the acrolein / methacrolein / urea copolymers are finally made by combining acrolein, methacrolein and urea in one Mole ratio typically copolymerized in the vicinity of 4.0: 0.8: 0.2. In the case of the various copolymers according to the invention the acrolein can be replaced by methacrolein, the ratios remaining the same. The exact structure the copolymers according to the invention are not known.

The tin or tin (II) ions are usually in the form of an in Water-soluble tin (II) salt, e.g. as tin (II) sulfate or Tin (II) fluoborate introduced into the tinning baths. Examples for free acids contained in the baths are sulfuric and fluoboric acids or an aromatic sulfonic acid, such as e.g., benzenesulfonic acid. The concentration of tin and freer Acid in the baths can be varied between fairly large limits, as known to those skilled in the art, with a concentration of tin from 15 to 100 g / l (calculated as Sn) and

109886/19 8-4

a free acid concentration of 35 to 200 g / l in general for the sulfate, fluoborate and aromatic sulfonate type baths are generally maintained. The present The invention is explained in more detail below with reference to various preferred embodiments.

Those used according to the invention as glossers (glossing agents) Polymers (both the homopolymers and the copolymers) are preferably through a Schiff base completed to prevent cross-linking of the polymer, which would lead to a three-dimensional insoluble resin would whose usefulness is unsatisfactory. It is also possible to stabilize the polymer in such a way that that the degradation and decomposition are prevented. Also seem the end group (s). of the marine type Base to exert a shining effect on the electrolytic tin coating in addition to its stabilizing effect. Man prepares them by using a primary amine as a precursor of the terminal group of the Schiff base type of the polymerization reaction mixture (Homopolymerization or copolymerization) adds, with the result that a condensation reaction between the hydrogen atoms of the amine on the one hand and the oxygen atoms of the carbonyl radicals of the acrolein or methacrolein polymers on the other hand, this condition to the desired end groups of the type of a marine base which leads have the formula

-C = NR
I.
H

in which R denotes the radical of a primary amine according to the above definition and, for example, an aryl, heterocyclic or aralkyl.

To produce the end group (n ')' of the ship type see base one can use any suitable primary amine with the oxygen atoms

109886/1984

of the carbonyl radicals of the aldehyde in the polymerization reaction mixture react permit. If R in the formula given above of the terminal group of the Schiff type see base is aryl, then are examples of the phenyl, tolyl, xylyl or naphthyl radicals, if R is a heterocyclic radical, then R can be, for example, a pyridyl radical and if R finally a Aralkyl radical means, it can be a benzyl radical.

As used herein, the term "residue of a primary amine" designated Ψ net to after the reaction of hydrogen atoms to see the amino moiety of the primary amine with the oxygen atom of the Carbonylrestes of acrolein or Methacroleinpolymerisate to a condensation reaction to form end groups of the type of Schiff base remaining part of the primary amine to the exclusion of the nitrogen atom and the hydrogen atoms of the amino radical. Any suitable amine which is capable of stabilizing the polymer or copolymer can be used to prevent crosslinking and decomposition which forms the terminal group of the Schiff base type. Examples of suitable primary amines are mono- and bicyclic aromatic primary amines, such as the o-, m- and p-toluidines, aniline, the t xylidines, e.g. 2,3-dimethylaniline, 2,4-dimethylaniline, 2,5- Dimethylaniline, 3 »4-dimethylaniline, 5f5-dimethylaniline and oc-naphthylamine, heterocyclic primary amines, such as aminopyridines, such as 2-aminopyridine and 3-aminopyridine, and aralkylamines, such as benzylamine.

Preferably, the end groups are of the marine type Base by condensation reaction of a primary aromatic amine, in particular aniline or o-, m- or p-toluidine with . formed a carbonyl radical. The end group or groups of the type a Schiff base have the following formula if aniline or o-, m- or p-toluidine is used as a precursor:

109886/1984

in which R is -CEU or -H; among the! oluidines that is o-Toluidine preferred.

Preferably, the primary amine precursor of the end group (s) of the marine base type of the polymerization reaction mixture in the preparation of the polymer in a molar ratio of about 1: 2.5 to about 1: 7.5 and preferably of about 1: 4 up to about 1: 6 from primary amine to ά, β-ethylenically unsaturated Aldehyde, i.e. acrolein or methacrolein in the case of homopolymers * or the sum of acrolein or methacrolein and the different, ethylenically unsaturated, copolymerizable Aldehyde, i.e. e.g. from methacrolein or acrolein or erotonaldehyde, in the case of those different from them α, β-ethylenically unsaturated copolymerizable aldehyde obtained Copolymer added. In the case of those with a copolymerizable reagent which does not contain α, β-ethylenically unsaturated Is aldehyde, copolymers obtained, the molar ratio mentioned above is the ratio from primary amine to acrolein or methacrolein alone. If the acrolein is the comonomer in a predominant amount, it will run off the polymerization reaction is generally very rapid; in this case the duration of the polymerization is preferably about 20 to 120 minutes to prepare a sparingly soluble in an organic solvent such as isopropanol To prevent polymer. The polymers used according to the invention are preferably in a suitable liquid organic Solvent, e.g. in isopropanol, dissolved as soon as the polymerization is considered to have ended completely and immediately after the polymer has been separated off from the liquid aqueous reaction mixture.

1 09886/1984

The tinning baths are preferably sulfate baths, in which the free acid is sulfuric acid and in which the tin or tin (II) ions are supplied by tin (II) sulfate will.

en
The quality or Properties of the homopolymers and copolymers used according to the invention are illustrated in more detail by the following examples.

Example 1 '*
Part _- A

To 50 ml of ambient temperature water inside a reaction vessel 37 * 5 g (0.67 mol) of acrolein are added. 6 g of sodium carbonate and 13.8 g are then added to this mixture (0.13 mol) o-toluidine as a precursor for an end group of the type a ship to see base for the acrolein end polymer. The reaction mixture is stirred for 20 minutes. You get an im essential linear acrolein homopolymer with low PM (molecular weight), with chains terminated by end groups of the type a ship's see base complete that out of the liquid precipitates in the form of a yellow, resinous solid, which one separated by decantation, washed with water and dissolved in 300 ml of isopropanol solves.

PartYY

3 ml of the propanol solution of the above-mentioned acrolein homopolymer s with chains, which are terminated by groups of the type of a Schiff base, become an aqueous, acidic electrolytic Bath with sulfate added to the following composition:

Tin (II) sulfate 30 g / l

Sulfuric acid 100 ml / 1

37 # aqueous formaldehyde solution 7 ml / 1

109886/1 # 84

The sulfuric acid used to make such a bath has a concentration of $ 98. You also give 2 ml of one A * thoxynonylphenol ~ type surfactants. Then leads tinning in a Hull test cell under the the following conditions: effective amperage = 1 to 3 Ampere, bath temperature = normal ambient temperature, tinning time = 5 minutes. The electrolytic tin plating on the Hull test plate has a good gloss within the Current strength range between approximately 1.07 and 8.6 A / dm.

Example 2 {

Part A

A low PM acrolein homopolymer which is essentially linear and has chains terminated by Schiff base-type groups is prepared by a procedure essentially identical to that described in Experiment Mr. 1, Part A. , but with the difference that this time 12 g (0.12 mol) of aniline are used as a precursor of the Schiff base. The acrolein homopolymer obtained in this way with low PM and with essentially linear chains which are terminated by groups of the type of a Schiff base d is dissolved in 300 ml of isopropanol.

PartJB

3 ml of the isopropanol solution obtained in Part A above will be used to an acidic sulphate electrolytic tinning bath having a composition substantially that of the in example 1, part B, corresponds to the bath used. 2 ml of a surfactant is also added to this bath of the athoxynonylphenol type to. Electrolytic tinning is done carried out in a Hull test cell under working conditions (current intensity, temperature of the bath and duration of the formation of the

109886/1984

Coating), essentially with those as they are in the experiment Mr. 1,. Part B applied are identical. The on electrolytic tin coating formed on the Hull test panel has a nice sheen within the current range about 1.07 and 8.6 A / dm.

Example 3
Part A

23.5 g (0.42 mol) of acrolein and 23.5 g (0.33 mol) of crotonaldehyde are dispersed in 150 ml of water at ordinary ambient temperature inside a reaction vessel. The mixture is stirred vigorously and 13.8 g (0.13 mol) of o-toluidine are added as a gate runner the Schiff see base for the formation of the end groups of the chains of the final copolymer and 6 g of sodium carbonate. After 20 minutes An acrolein / crotonaldehyde mixture polymer precipitates from the liquid with low PM and with essentially linear chains terminated by groups of the marine base type are in the form of a brown, resinous solid that is separated by decanting, washed with water and is then dissolved in 300 ml of isopropanol.

Part B

3 ml of the isopropanol solution of the above-mentioned acrolein / crotonaldehyde copolymer are an acidic sulfate type electrolytic tinning bath having a composition which is essentially the same as in Example 1, Part B,. used bath is identical, given. Become this bathroom another 2 ml of a surfactant of the ethoxynonylphenol type was added. The electrolytic tinning is carried out in a HuIl test cell carried out under working conditions (current strength, temperature of the bath and duration of the formation of the coating) that essentially identical to that used in Example 1, Part B

109886/1984

are table. The electrolytic formed on the Hull test plate Tin plating has a beautiful sheen within the current range of 0.07 to 7.5 A / dm.

Example 4
Part A

To 250 ml of water at ordinary ambient temperature in a reaction vessel are added 37.5 g (0.67 mol) of acrolein and 10 g a 37% aqueous formaldehyde solution. While stirring the liquid mixture, 4 g of sodium carbonate and 13.8 g are added (0.13 mol) o-toluidine as a precursor of a Schiff base for Formation of the end group of the chains of the desired copolymer, An acrolein / formaldehyde copolymer is obtained for 20 minutes with low PM and with essentially linear chains terminated by groups of the marine base type are in the form of a pale yellow, resinous, semi-solid substance that is dissolved in 300 ml of isopropanol.

Part B

3 ml of the isopropanol solution of the above copolymer with chains terminated by groups of the Schiff base type, an acidic electrolytic tinning bath is used of the sulfate type having a composition substantially identical to that of the bath used in Example 1, Part B is identical, admittedly. Another 2 ml of a surfactant of the ethoxynonylphenol type are added to this bath and the electrolytic tinning is carried out inside a HuIl test cell under working conditions (current intensity, temperature of the bath and duration of the formation of the coating), which with are identical to those used in Example 1, Part B. The electrolytic formed on the Hull test plate Tin plating has a beautiful sheen within the current range of 1.07 to 8.6 A / dm.

109 ^ 86/1984

Example 5
Part A

40 g (0.42 mol) of 9C methacrolein are added to 100 ml of water at normal ambient temperature in a reaction vessel. The mixture is stirred vigorously and 1 g of sodium hydroside is added to it and 13t8 g (0.13 mol) of o-toluidine as a precursor of Schiffsehen Base for the termination of the chains of the Methacroleinendpolymerlsats to. After 20 minutes it falls out of the liquid. a methacrolein homopolymer with low PM and with in the we- " essential linear chains, which are terminated by groups of the type of a ship see base, in the form of a pale yellow, resin-like, semi-solid material that is separated by decanting, washed with water and then dissolved in 150 ml of isopropanol.

PartJB

3 ml of the isopropanol solution of the above homopolymer with chains completed by groups of a ship type see base are, an acidic electrolytic sulfate-type condensation bath having a composition that is essentially " borrowed is identical to that of the bath used in Example 1, Part B, added. Add 2 inl of a surface-active agent to the bath By means of the ethoxynonylphenyl type to and conduct the electrolytic tinning inside a Hull test cell under working conditions (current intensity, temperature of the bath and duration of the formation of the coating), which with those, as used in Example 1, Part B, are identical. The electrolytic tin coating formed on the Hull test panel has a beautiful gloss within the current range from 1.07 to 7.5 A / dm.

109886/1984

Example 6
Part A

To 100 ml of water at normal ambient temperature inside a reaction vessel is given 30 g (0.53 mol) of acrolein and 7.5 g (0.09 moles) of methacrolein are added. 4 g of sodium carbonate and 13.8 g (0.13 mol) of o-toluidine as precursors are added to the mixture obtained the naval base for completing the chains of the Acrolein / methacrolein final copolymer. After the mixture has been stirred for 20 minutes, an acrolein / methacrolein copolymer precipitates from the liquid with low PM and with essentially linear chains formed by groups of the marine base type are completed, in the form of a yellow, resinous, semi-solid substance, which is separated by decanting, washed with water and then dissolved in 150 ml of isopropanol.

Part B

3 ml of the isopropanol solution of the above copolymer with chains terminated by groups of the Schiff base type are used in an acidic electrolytic tinning bath of the sulfate type having a composition which is essentially identical to that of the bath used in Example 1, Part B is added. 2 ml of a surface-active agent of the ethoxynonylphenol type are added to this bath and the electrolytic tinning is carried out inside a Hull test cell under working conditions (current intensity, temperature of the bath and duration of the formation of the coating) which are similar to those described in Example 1, Part B, applied are essentially identical. The electrolytic tin coating formed on the Hull test plate has a beautiful gloss within the current range of 1.07 to 6.5 A / dm ² .

109886/1984

BeisOJel 7
Part A

An acrolein / methacrolein / urea copolymer with a low ΪΜ and with essentially linear chains running through Groups of the type of a Schiff base are completed, is prepared by a method which is the same as in Example 6, Rope A, the procedure used is essentially identical where-, using the same substances and reagents in the same amounts r and under the same working conditions as in example 6, Part B, used, but with the difference that this time before the addition of the sodium carbonate and the o-toluidine, the aqueous Mixture of dispersed acrolein and methacrolein adds 7.5 g of urea as reagent or additional comonomers. That acrolein / methacrolein / urea copolymer obtained in this way with low EM and with essentially linear chains terminated by groups of the Schiff base type, which is in the form of a yellow, resin-like, semi-solid substance, is dissolved in 150 ml of isopropanol.

Part _- B. "

3 ml of the isopropanol solution of the above-mentioned acrolein / methacrolein / urea copolymer are a sulfate-type acid electrolytic tinning bath, which is a composition which is essentially identical to that of the bath used in Example 1, Part B, is added. To this Bath will also add 2 ml of ethoxynonylphenol-type surfactant added and the electrolytic tinning is carried out in a Hull test cell under working conditions by (current intensity, temperature of the bath and duration of the formation of the coating) with those used in Example 1, Part B. are essentially identical. The one on the Hull trial plate The electrolytic tin coating formed has a beautiful luster

109886/1984

within the current range of 1.07 to 5 »4 A / dm. Example 8

! 2 ml of to in Example 1, ^r ^ eil A, manner described are hergestelltenlsopropanollösung to an acidic aqueous electrolyte see tinning with lluoborat and the following composition was added:

Tin (ll) fluoborate 50 g / l

Fluoboric acid (48%) 100 g / l

37% aqueous iormaldehyde solution 10 g / l

0.5 ml of a surfactant of the ethoxynonylphenol type is also added to this bath and the electrolytic tinning is carried out inside a Hull test cell under the following operating conditions: effective amperage = 3 amperes; Bath temperature = normal ambient temperature; Duration of the formation of the electrolyte! See tin coating = 5 minutes. The electrolytic tin coating on the Hull test plate has a good gloss within the current range of 1.07 Mb 4.3 A / dm ² . -

Example 9

2 ml as described in Example 3, Part A produced isopropanol solution of the copolymer are one acidic, aqueous electrolytic tinning bath with eluoborate and a composition substantially identical to that of the bath described in Example 8 was added. to 0.5 ml of a surfactant of the ethoxynonylphenol type is also added to this bath and electrolytic tinning is carried out inside a Hull test cell under working conditions (current intensity, temperature of the bath, duration of formation of the coating), which are essentially identical to those used in Example 8. The one formed on the Hull test plate

109886/1984

Electrolytic tin plating has a good gloss within the current range of about 1.07 to 4.3 A / dm.

In further examples using a Hull test cell as well as an acidic, electrolytic tinning bath with tin (II) sulfate and a composition which is essentially with that of the bath used in Example 1, Part B, were carried out, the addition of an acrolein / Vinyl acetate copolymer, which is in a molar ratio of 4: 1 copolymerized to the bath to form a

Ψ electrolytic tin coating with a fairly good gloss on the test plate. The copolymer of the above experiment had chains terminated by groups of the Schiff base type by adding o-toluidine to the reaction mixture, and a nonionic surfactant was also added to the tinning test bath. The acrolein separately added to a tin (II) sulfate containing acidic electrolytic tinning bath having a composition substantially identical to that of the bath used in Example 1, Part B, results in the formation of a non-glossy electrolytic tin coating the Hull test plate within the entire current range.

In addition, the strong tear irritability, together with its toxicity and irritant property, make acrolein difficult usable.

The production of bright electrolytic tin coatings according to the invention is advantageous in the production of electrical contacts, electronic assemblies, iron objects (Household items) and extravagant jewelry. The coatings are soft and suitable for welding or soldering operations.

Regardless of the embodiment used, means for producing tin coatings are available in this way, their advantageous properties are described above. Self-

109886/1984

The invention is not to be understood in any of the described embodiments and applications of its various parts which are only used to illustrate the invention, but rather it also includes all amendments.

109886/1984

Claims (19)

Claims 1.J Acid aqueous bath for the electrolytic deposition of shiny tin, which contains tin ions, free acid and a nonionic surface-active agent, characterized in that that as a G-lancer (shining agent) it is a soluble, im contains essential linear acrolein or methacrolein polymer. 2. Bath according to claim 1, characterized in that the chains of the polymer are formed by groups of the marine base type r complete. 3. Bath according to claim 2, characterized in that the polymer has been prepared by a polymerization process in which the polymerization reaction mixture is a precursor the end group of the Schiff base type, consisting of a primary amino compound, is added in such an amount, that the ratio of the amount of the precursor to the amount of a polymerizable reagent of the α, β-ethylenically unsaturated Aldehyde / which is also present in the mixture is between about 1: 2.5 and about 1: 7.5. 4. Bath according to claim 3, characterized in that the end group of the marine base type of the polymer has the formula: - CH = NO
in which R is the residue of a primary amine. 5. Bath according to claim 4, characterized in that R is an aryl radical is. 6. Bath according to claim 5, characterized in that the terminal group of the marine base type is the following formula 109886/1984 sits: -CH = N - in which R means -CH, or -H ". 7 .. bath according to claim 2, characterized in that the polymer has a molecular weight between about 300 and 900. 8. Bath according to claim 7, characterized in that the polymer a compound from the group of acrolein homopolymers, Methacrolein homopolymers, the copolymers of acrolein with a different copolymerizable Compound, especially with acrolein, crotonaldehyde, formaldehyde, acrylamide, vinyl acetate, and the copolymers of methacrolein with a different copolymerizable compound is used. - 9. Bath according to claim 1, characterized in that the acrolein or methacrolein polymer by a polymerization process has been produced, in which the polymerization of acrolein or methacrolein in an aqueous, liquid, alkaline medium, preferably a dilute aqueous solution of a weak base is carried out. 10. Bath according to claim 9 »characterized in that the weak base is an alkali metal carbonate, in particular sodium carbonate or potassium carbonate is used. 11. A method for the electrolytic deposition of shiny tin, characterized in that there is a direct electrical current conducts from an anode to a cathode which is immersed in a bath according to any one of claims 1 to 10. 1 09886/1984 12. A process for the electrolytic deposition of shiny tin, characterized in that a direct electrical current is passed from an anode through an aqueous, acidic tin-plating bath conducts to a cathode on which the tin is electrolytically deposited, the bath being tin ions, free acid, a nonionic surface-active agent and a soluble, essentially linear, α, ß-ethylenically unsaturated aldehyde polymer with a structural unit of the formula RH
II
CH ₂ = CC = 0 in which R is a hydrogen atom or a methyl radical. 13. The method according to claim 12, characterized in that the polymer has chains by groups of the type one Ship Viewing Base are complete. 14. Additive composition for the production of baths according to any one of claims 1 to 10, characterized in that it a mixture of a soluble, essentially linear, <x, ß ~ ethylenic unsaturated aldehyde polymer whose structural unit has the formula RH
II
CH ₂ ss CC = 0 in which R is hydrogen or methyl, with a water-miscible diluent for the polymer. 15. Additive composition according to claim 14, characterized in that that it contains a polymer with chains terminated by groups of the type of a Schiff base are. 109886/1984 16. Additive composition according to claim 15 »characterized in that that it is in the terminal group of the type of a Schiff base of the polymer is such as it is in the baths according to one of claims 4 to 6 is described. 17. Additive composition according to claim 16, characterized in that that the polymer has a molecular weight between about 300 and 900. 18. ' Additive composition according to claim 14 »characterized in that that the diluent is an alkanol having 1 to 3 carbon atoms, in particular isopropanol. 19. Additive composition according to claim 15 »characterized in that that the polymer from the group of the acrolein homopolymers, methacrolein homopolymers, the copolymers of Acrolein with one of these different, copolymerizable Compound and the copolymers of methacrolein with a different copolymerizable compound. 109886/1984